1) Field of the Invention
The present invention relates generally to lawn and garden tractors or similar vehicles, and more specifically to an interlock circuit for such a vehicle.
2) Related Art
Vehicles such as some lawn and garden tractors with PTO driven attachments include an interlock circuit with several functions including the prevention of PTO operation when the vehicle is placed in reverse. Under certain conditions, operation of the PTO while the vehicle is in reverse is necessary. Various override systems have been proposed for this purpose, but many are difficult or inconvenient to operate. For example, one type of available override system on a mower allows PTO operation when the vehicle is backing up, but only after the PTO is automatically disconnected during the shift into reverse. Another type requires the operator to continuously push a switch during reverse operation. A further type is shown in U.S. Pat. No. 5,994,857 of common ownership with the present application, wherein several relays and a PTO switch provided with a momentary on position establish a temporary mow in reverse function. Prior circuits such as the one shown in the 5,994,857 patent commonly utilized a single pole seat switch and required extra circuitry to assure proper operation of interlock functions which rely on PTO, brake and operator presence conditions on the vehicle for enabling PTO operation in reverse. Providing an interlock circuit without need for multiple relays and with an override feature that is simple, convenient, and reliable has been a source of difficulty.